Fatigue and Circadian Rhythms Flashcards
Jet lag (desynchronosis) has become more common with increasing international travel. Typically, _______ day(s) is required for each time zone crossed for full adjustment.
1 day for each time zone crossed.
Most modern air forces have a fairly consistent loss of ______ percent of pilot trainees due to persistent motion sickness.
1-2%
True or false; more experienced pilots tend to suffer simulator motion sickness
True
A Phased Response Curve is described for bright light exposure in which carefully timed light can adjust the established circadian rhythm. Exposure to light as bright as that given off by an ordinary lightbulb a few inches away (about 1000 lux) can cause a phase delay (Westward adjustment) or a phase advance (Eastward adjustment). In a normally entrained individual , what time would a phase advance be caused by light exposure?
a) 0100-4000
b) 0400-0700
c) 2200-2400
d) Descending core temperature
b) 0400-0700. Exposure to about 1000 lux during 0400-0700 is normall entrained individuals can cause a 2-3 hour phase advance, a shift towards a normal circadian pattern 2-3 times zones to the east. At 0400 the temperature just begins its rising phase. The temperature descends between 0100-0400. Light at 0100 to 0400 will shift to the West.
Circadian cycle desynchronization, occuring during long distance air travel through several time zones, can result in aircrew fatigue if insufficient rest between flights is obtained.
Normally, readjust occurs at a rate of_________.
1 day/1 time zone
Your airline company has to operate a three shift maintenance base and asks you to recommend the best theoretical shift schedule. You suggest the following rotation:
a) shift from day to night to evening at weekly intervals
b) shift from evening to day to night at weekly intervals
c) shift from day to evening to night at every three week intervals
d) shift from day to night to evening at an interval of every three weeks
e) shift from day to evening to night at weekly intervals
c) shift from day to evening to night at intervals of every three weeks.
A standard EEG topography accompanies different stages of sleep. Indeed, sleep is usually defined by these patterns. It is more difficult to awaken from one pattern of sleep than the other patterns and this has implications for timing of naps, so called power naps. Which pattern is this?
a) Rapid Eye Movement sleep
b) K complexes
c) Slow Wave Sleep
d) Paradoxical Sleep
e) High frequency, low amplitude
c) Slow Wave Sleep- It is more difficult to awaken from the low frequency, high amplitude Slow Wave Sleep. It is stages 3 and 4 in which delta waves dominate the EEG. Dreaming is during REM sleep.
Caffeine is the most psychoactive of all the methylxanthines and probably acts centrally as an adenosine antagonist. It can be a powerful and effective stimulant if used carefully in doses titered to an individual’s tolerance. Which of the following is NOT true of caffeine?
a) has a 5-6 hour half life
b) is found in decaffeinated preparations and chocolate substances
c) has a more prolonged effect of pregnant women and women taking oral contraceptives
d) has a reduced half life in heavy smokers
e) must be in doses over 100mg to affect cognitive performance.
e) Doses as low as 32mg can impact human performance
Diurnal day-night cycle effects are contributors to loss of proficiency is the same sense as fatigue effects. Which of the following statements best describes the relationship between the two?
a) Diurnal variation is a primary factor in decrement in prolonged work.
b) Diurnal variation is less a factor in active tasks than in inactive tasks.
c) Early morning flights, which require easly awakening and the concomitant alteration of normal sleep schedules and/or duration, enhance the role of diurnal variation as a primary stressor.
d) Diurnal variation is a stressor secondary to fatigue, increasing performance decrements when the aircrewman has already been on duty for some time.
d) Diurnal variation is a stressor secondary to fatigue, increasing performance decrements when the aircrewman has already been on duty for some time.
Sleep follows biological rhythms. Which of the following is true in “good sleepers”?
a) minimum body temperature occurs at sleep onset
b) minimum body temperature occurs about 2 hours after falling asleep
c) Minimum body temperature occurs about 4 hours after falling asleep
d) Minimum body temperature occurs about 6 hours after falling asleep
e) Minimum body temperature occurs just before awakening
c) Minimum body temperature occurs about 4 hours after falling asleep
